In the fabrication of semiconductor devices, methods may utilize optical proximity correction (OPC) models to compensate for image errors and process effects in a resulting device. However, such models may assume a perfect mask pattern. Penetration ratio basically refers to a mask corner rounding effect which arises from imperfect mask fabrication. Errors in the mask, for instance, a 1 nm error, may result in errors of five times in the substrate, for instance, a 5 nm error. Existing mask parameters in conventional OPC software are unable to capture the mask corner rounding effect.
A need therefore exists for methodologies and an apparatus for enabling OPC models to account for errors in the mask such as the corner rounding effect.